Hypertension is defined as a symptom with a systolic blood pressure of 140 mmHg or more or a diastolic blood pressure of 90 mmHg or more in the WHO/ISH guidelines. It is reported that there are currently about 40 million patients in Japan and about one billion patients in the world who suffer from hypertension (Dicision Resources, Inc.). Continuous hypertension causes the onset of cerebral hemorrhage, cerebral infarction, aortic aneurysm, nephrosclerosis, myocardial infarction, heart failure or the like, finally resulting in death. A large-scale clinical trial shows that administration of an antihypertensive drug inhibits these diseases. Currently, there are efforts being made to actively lower blood pressure by administration of an antihypertensive drug, exercise, improvement of dietary habit and the like; however, further sufficient blood pressure control is desired.
A main mechanism of hypertension is activation of the renin-angiotensin system (hereinafter sometimes referred to as R-A system). The R-A system is a typical vasopressor system in the living body which increases blood pressure by storing sodium (salinity) in the body to increase circulating blood volume or constrict vascular smooth muscle. In the R-A system, renin converts angiotensinogen to angiotensin I, and angiotensin converting enzyme (hereinafter sometimes referred to as ACE) converts angiotensin I to angiotensin II. Angiotensin II is assumed to act on angiotensin type-1 receptors (hereinafter sometimes referred to as AT1) to cause vasoconstriction, cell proliferation or collagen production and to cause hypertension and subsequent organ failure. Currently, ACE inhibitors inhibiting production of angiotensin II (hereinafter sometimes referred to as ACEI) and angiotensin receptor blockers inhibiting stimuli to AT1 (hereinafter sometimes referred to as ARB) are used as antihypertensive drugs. These drugs are known to have significant hypotensive and organoprotective effects.
Renin is an aspartic protease converting angiotensinogen to angiotensin I and assumed to be a rate-limiting enzyme in the R-A system. Accordingly, renin inhibitors are considered to efficiently inhibit the R-A system and are expected to have the same hypotensive effect as those of ACEI and ARB (Circulation, 2005, vol. 112, p. 1012-18).
There are known some δ-amino-γ-hydroxy-ω-alkanoic acid amide compounds having renin inhibitory activity (see Patent Document 1 or 2, for example). There is also known a δ-amino-γ-hydroxy-ω-alkylalkanoic acid amide compound in which the carbon atom at the 2-position α-position) is substituted with a nitrogen atom (see Patent Document 3 or 4, for example) or in which the carbon atom at the 8-position is substituted with a nitrogen atom (see Patent Document 5, for example). However, there has not been known a δ-amino-γ-hydroxy-ω-alkylalkanoic acid amide compound which has a cyclic group at the 7-position or in which the carbon atom at the 7-position carbon atom is substituted with a nitrogen atom. The compound of the present invention differs greatly in structure from the above known compounds in that the compound has a cyclic group at the 7-position or the carbon atom at the 7-position is substituted with a nitrogen atom.    Patent Document 1: U.S. Pat. No. 5,559,111    Patent Document 2: Japanese Patent No. 3240322    Patent Document 3: WO 2005/070870    Patent Document 4: WO 2005/090304    Patent Document 5: WO 2005/051895